[CONTRIBUTION
FROM THE
CHEMISTRY DEPARTMENT OF FLORIDA STATE UNIVEBBITY]
T H E POTENTIOMETRIC MEASUREMENT OF ACID DISSOCIATION CONSTANTS AND pH I N THE SYSTEM METHANOL-WATER. pK, VALUES FOR CARBOXYLIC ACIDS AND ANILINIUM IONS A . L. BACARELLA, ERNEST GRUNWALD, H . P . MARSHALL, E. LEE PURLEE
AND
Received January 84, 1966
In recent years, acid dissociation constants have become increasingly important as tools in determining molecular structure and in solving questions of organic theory (1, 2). Many measurements have been made using a commercial pH meter and the cell glass electrode/solution X/KCI (sat ., aq.)/HgpC12-Hg
VI.
In this method of measurement it is convenient, by use of a buffer of known pH (3) and of the zero adjustment knob of the meter, to make the potentiometer scale direct-reading in pH units. However, the choice of a standard buffer solution requires some care since the method requires that the junction e.m.f. at the solut,ion X/I
